Why did british think colonist should pay taxes

I know that They were following the rules of Mercantilism to keep foreign goods out. There's most likely more to this, though. I just looked this up and they (the british) needed to pay war debt,  which is another reason Colonists were unhappy. They thought the colonists owned them beacause of the French and Indian war success

To pay their part of the cost of the huge debt. The colonists claimed that they should not be taxed by the Parliament directly or be taxed only with their consent.

the process of industrialization is called a revolution because